1) To use the NIH GUI, run the NIH_GUI.py file 
2) When the GUI appears, press the 'Load a session folder' button to load in the session you'd like to use
3) You can optionally load in a video as well
4) You can save frame intervals for specific conditions by choosing them from the dropdown menu and typing in starting and ending frames, and saving them to the table
5) Running the balance assessment will calculate path length for the intervals and bring up path length histograms of the data
6) Choose a name for the folder that will contain the data analysis results - this folder will be saved within the 'data_analysis' folder in your session 
7) Press 'Save out data analysis' results to save out data